I've just started squiggly sudokus, so maybe I'm missing something. I was only able to add a couple of 4's (C4R7 and C8R4), and that 7's are locked in R8 in the lower left shape, fours are locked in C2 in the upper left shape, and the obvious 34 pairs in C5R1 and C5R9.

When I ask for a hint from the developmental, bleeding edge version, it provides a 5 at C4R6, but the message is "*Dev interface cannot currently explain this hint*".